The invention relates to connectors for joining panel or junction boxes to a cable having a conduit surrounding the cable. The invention has particular application to metallic clad jacketed cable (MJC) and liquid tight flexible conduit joining such cable or conduit to panel, junction and other boxes.
A wide variety of connectors for joining cables and conduits to panel, junction and other boxes are known. Typically they have a right hand thread to join with the box and another right hand thread to join to the cable or conduit.
The prior art also includes the following U.S. Pat. Nos.: 1,349,518 August 1920; 1,657,253 January 1928; 2,470,423 May 1949; 2,772,323 November 1956; 2,825,750 March 1958; 3,206,833 September 1965; 3,605,069 September 1971; 3,716,653 February 1973; 3,869,186 March 1975; 4,454,376 June 1984; and 4,479,689 October 1984.
The prior art obviously includes mechanical devices such as the turnbuckle. This device is essentially a sleeve that has respective left and right hand threads at the axial extremities thereof. Typically it is used to draw two things together. For example, it is often used to raise a sagging screen door by joining (1) a point near the bottom away from the hinges to (2) a point higher up on the door near the hinges with respective threaded members that engage the axial extremities of the turnbuckle. Rotating the sleeve in a single direction causes the threaded members to be drawn into the sleeve and thus raises the lower corner of the screen door that is remote from the hinges. The U.S. Pat. No. 4,454,376 discloses a connector for connecting the ends of two wires. The connector incorporates two axial extremities that are each structured like wire nuts. The wire nut, such as that described in U.S. Pat. No. 2,825,750 is typically a plastic shell provided with a helical conical threaded insert in which two wires are twisted to join the wires. The patent describes essentially two wire nuts at the axial extremities that are respectively left and right hand threaded. Thus, rotation of the device in one direction will tighten the connection to both wires simultaneously and rotation in the opposite direction will loosen the connection to both wires simultaneously.
U.S. Pat. No. 2,470,423 also describes a connector for electrical conductors that utilizes left and right hand threads in a similar manner.
U.S. Pat. No. 4,479,689 discloses an electrical connector having left and right hand threaded elements that work together.
It is an object of the invention to provide apparatus that is very easy to install.
It is an object of the invention to provide apparatus which is inexpensive to manufacture as well as requires a minimum of labor to install.
Still another object of the invention is to provide apparatus that has only a single part and thus has no loose parts that are vulnerable to getting lost.
Yet another object of the invention is to provide a moisture tight seal at the interface between the conduit jacket or cable jacket and the connector.
Another object of the invention is to provide a ground connection between the metal clad of the conduit and the box.
An additional object of the invention is to provide a positive connection that will minimize the possibility of the cable or conduit being pulled out of the connector.